1. Field of the Invention
The present invention relates to a digital broadcast receiver and, in particular, to a fast channel switching method and apparatus for a digital broadcast receiver having a single tuner.
2. Description of the Related Art
A digital broadcast receiver is an apparatus that restores original digital data from a broadcast signal transmitted by a broadcast station. The digital data is coded and modulated so as to be broadcast in the form of a broadcast signal by the broadcast station. The digital broadcast receiver demodulates and decodes the broadcast signal for recovering the original digital data. The digital broadcast receiver is provided at least with a tuner, a demodulator, and a decoder.
Digital broadcast systems are classified into a digital multimedia broadcast (DMB) system or a digital video broadcasting (DVB) system. These digital broadcast systems provide a plurality of service channels in a frequency band and each service channel is structured with multiplexed sub-channels of video, audio, and program information data.
Current mobile devices are typically powered by multimedia processors that support various multimedia functions including digital broadcast reception. With the integration of the multimedia functions, the mobile devices are becoming much complex in physical configuration and execution procedures. Here, the mobile devices include mobile phones, Smartphone, laptop computers, Personal Digital Assistants (PDAs), etc.
A digital broadcast channel is divided into a number of service channels for delivery of audio, video, data, and multimedia, such that a broadcast receiver scan the broadcast channel for retrieving the service channels. Since the digital broadcast channel consists of a plurality of service channels, channel navigation for searching a target channel may be a cumbersome labor.
In digital broadcasting, particularly, the digital data is highly compressed and thus it takes a considerable amount of time for a screen to become stable after switching to a service channel. This is unlike switching channels in an analog broadcasting system. This is because of a processing delay caused by demodulation and decoding of the broadcast signals of the selected service channel. Accordingly, the broadcast data corresponding to the delay time are lost or an out-of time image is displayed on the screen.
In the case of DVB, data bursts come up every 1 to 4 seconds. Accordingly, if a channel switching event occurs while receiving a service channel, the screen shows nothing before the data burst assigned to the target channel comes up, resulting in inconvenient to subscribers.